Field
The present disclosure generally relates to heat-transfer techniques. More specifically, the present disclosure relates to a heat pipe that includes a binary working fluid including a composition proximate to and less than or equal to the azeotropic point on a thermodynamic phase diagram.
Related Art
The computational performance of electronic devices has increased significantly in recent years. This increased performance has been accompanied by an increase in power consumption and associated heat generation. Furthermore, this additional heat generation has made it harder to maintain acceptable internal and external operational temperatures in these electronic devices.
Heat pipes are a common, passive heat-transfer mechanism in electronic devices that leverages thermal conductivity and phase transitions to efficiently manage the heat transfer. In particular, at a hot interface of a heat pipe, a liquid phase of a working fluid in contact with a heat source via a thermally conductive solid surface turns into a gas phase by absorbing heat from the solid surface. Then, the gas travels along the heat pipe to a cold interface (which is thermally in contact with a heat sink) and condenses back into a liquid, thereby releasing the latent heat. Next, the liquid returns to the hot interface via capillary action, centrifugal force, and/or gravity, and the cycle repeats. Because of the very high heat-transfer coefficients for boiling and condensation, heat pipes are typically highly effective thermal conductors.
The working fluid used in heat pipes is often chosen to have good thermodynamic and thermal transport properties. For example, many heat pipes use water as the working fluid. Water has a very large heat of vaporization, which can allow large quantities of heat to be removed by evaporating a small amount of water. However, water has a relatively high boiling point of 100 C, which can restrict the temperature gradient between the heat source and the heat pipe and, thus, can limit the amount of heat that is removed.
Hence, what is needed is a heat pipe without the above-described problems.